Arterial partial pressure of oxygen and diffusion function as prognostic biomarkers for acute pulmonary embolism

Risk stratification for acute pulmonary embolism (PE) ignores the roles of respiratory function and gas exchange. We aimed to identify the role of arterial partial pressure of oxygen (PO₂) and diffusion function as prognostic biomarkers.

We collected the data from hospitalised patients with acute PE. We used Spearman's correlation coefficient and Cox regression analysis to explore the clinical and prognostic values of PO₂ and predicted percentage diffusing lung capacity for carbon monoxide (DLCO%pred) to predict the 30-day mortality.

We included 309 patients (mean age: 67.93 ± 13.31 years); 46.6% were men, and 12.62% were haemodynamically unstable. The 30-day all-cause mortality rates in the high-, intermediate high-, intermediate low-, and low-risk groups were 7.7%, 4.7%, 2.9%, and 0.0%, respectively (P < 0.05). PO₂ (P = 0.012) and DLCO%pred (P = 0.036) were significantly different between the four risk groups. There were strong correlations between PO₂, DLCO%pred, PO₂*DLCO%pred, and other markers (P < 0.05), especially troponin I, N-terminal pro-brain natriuretic peptide, and systolic pulmonary artery pressure. PO₂ and PO₂*DLCO%pred were prognostic factors for death in haemodynamically stable patients (hazard ratio [HR] 0.618, 95% confidence interval [CI] 0.389-0.980, P = 0.041, and HR 0.501, 95% CI 0.26-0.96, P = 0.036, respectively). A lower PO₂ (<8 kPa) was associated with a higher risk of mortality in all patients and in haemodynamically stable ones (HR 9.462, 95% CI 2.365-37.860, P = 0.001, and HR 6.597, 95% CI 1.102-39.495, P = 0.039, respectively).

PO₂, PO₂*DLCO%pred, and PO₂ < 8 kPa were predictors of 30-day all-cause mortality in all patients and haemodynamically stable ones.

ChiCTR2000030448.